Picked up a Strange Knight (見知らぬ騎士を拾いまして。) is a BL romance written by Taro(たろ). There are 19 chapters and two omake available on syosetu. The story is also published as an eBook by DeNIMO, available on Renta! after 2/27.
Link to the original: https://novel18.syosetu.com/n2163dg/
Summary from the Author: This is the story of the ordinary salaryman who picked up a strange man that turned out to be a knight, and the strange knight who began living with an ordinary salaryman in modern Japan.
Doggy-like knight x tsundere-feeling salaryman.
Sequel: Bringing My Wife Back from Another World
Summary from the Translator: Picked up a Strange Knight (見知らぬ騎士を拾いまして。) is a fluffy and heartwarming slice of life romance between an ordinary salaryman and a knight from another world.
The clueless knight Ilias Garland had somehow ended up in the foreign land of Japan, where he was rescued by the brusque and sassy salaryman, Sakurai Azusa. Upon realizing that Ilias had no way to get back home — wherever home was, because it certainly couldn’t actually be some place in another world, right? — Sakurai Azusa offered to let the knight stay temporarily in his apartment. And so the two of them began living together, and slowly falling in love.